SANTA CLARA, Calif. (AP) — Coach Kyle Shanahan is confident Jimmy Garoppolo has the physical tools to succeed as an NFL quarterback for the 49ers as evidenced by what he's shown over 10 starts in five seasons with San Francisco and New England.

Garoppolo's ultimate success will depend on how he handles some of the mental challenges of the position.

He got tested heavily last week. After throwing five straight interceptions in a forgettable practice against his own teammates, Garoppolo had a rough time in an exhibition against Denver — his first game action since suffering the major knee injury that ended his 2018 season before the end of the third game.

Garoppolo completed just 1 of the 6 passes he threw in three series at Denver, gaining zero yards and also throwing an interception for a 0.0 passer rating.

Shanahan called the first game back a "mental hurdle" and now Garoppolo has another one heading into a dress rehearsal game at Kansas City on Saturday, the site of his injury last September. After winning his first seven starts as a pro, Garoppolo hasn't had to deal much with failure or outside criticism since entering the NFL as Tom Brady's backup in 2014.

"When he has played, everyone has seen his ability and everyone knows he's in that club and everyone knows he not only has the ability to be in the NFL, he's got the ability to be one of the better ones," Shanahan said Thursday. "But, we've got to go through those ups and downs. It's not going to be, 'Is he good enough to do it?' We all know he's good enough to do it. It's going to be how he reacts to that and how we help him with that and that is what no one can account for, what these guys go through in this league at this position."

Garoppolo will have a hard time being worse than he was Monday night against the Broncos. The rough night started when his first pass was batted down at the line of scrimmage. His second throw was intercepted by cornerback Isaac Yiadom after he didn't communicate properly with the offensive line on a protection change or take a sack when he saw the play wasn't there.

Garoppolo didn't fare much better on the second series when his first pass was tipped again at the line and his second pass was broken up by cornerback De'Vante Bausby, who nearly had an interception return for a touchdown. Garoppolo threw one pass away under pressure on the third series before completing a screen for no yards to Matt Breida.

"Just little details here and there," he said. "Just got to be sharper with those things, starting with myself, and I think it'll help our offense going forward."

Garoppolo didn't have a chance to work his way out of his problems Monday night as he only played three series. He figures to get significantly more playing time Saturday in what should be his final game action before the start of the season.

Shanahan said Garoppolo and the offensive starters will likely play about a half against the Chiefs, although that could change depending on performance and play count.

Garoppolo said he believes it will be beneficial to go back to the stadium where he tore his left ACL while trying to cut back on a scramble.

"It'll be a good stepping stone," he said. "Definitely it'll be a little weird getting back there, but yeah, just trying to treat it like a normal game."

The 49ers are counting on a healthy and effective Garoppolo this season after winning just 10 games in the first two years under Shanahan. Garoppolo showed plenty of promise after arriving in San Francisco in a trade with the Patriots midway through the 2017 season. He stepped in after a few weeks and won all five starts, earning a five-year, $137.5 million contract to stay off the free-agent market.

Garoppolo completed less than 60% of his passes in his three starts last season before getting hurt. His yards per attempt dropped, while his sack and interception rates went up.

Now he's trying to prove he can get back to the level he was at near the end of 2017, even if his first try came up short.

"That's football," he said. "There's going to be ups and downs. As a quarterback, you just try to stay right in the middle the whole time and kind of just do what you do over and over and the results will take care of themselves."